RMweb Gold The Fatadder Posted October 29, 2011 RMweb Gold Share Posted October 29, 2011 I have finally taken the plunge and started to cut off the incorrect door handles on my Airfix E140 GWR B-set This means cutting out (from memory) 8 square cut outs for the recessed door handles on each side, (given the 4 coaches I need to treat that's 32 identical holes to cut, each a couple of mm square. Are there any special tools, or good methods that will make this easier? Link to post Share on other sites More sharing options...
Il Grifone Posted October 29, 2011 Share Posted October 29, 2011 I was going to do this but chickened out! (I do have four sets to do!) My thoughts involved either one 'large' hole and file square or four tiny holes and knife work. Neither really appealed and seeing the strong chance of making a co pig's ear of it I convinced myself they dont really show. I too would welcome an easy solution. (I thought about new etched sides, which would also solve the other problems of the extra window* and the weird glazing, but fails on the inconvenience and cost.) * I recently tried filling in one of these as an experiment, but have still not got it smooth enough. Link to post Share on other sites More sharing options...
Guest Natalie Graham Posted October 29, 2011 Share Posted October 29, 2011 I have finally taken the plunge and started to cut off the incorrect door handles on my Airfix E140 GWR B-set This means cutting out (from memory) 8 square cut outs for the recessed door handles on each side, (given the 4 coaches I need to treat that's 32 identical holes to cut, each a couple of mm square. Are there any special tools, or good methods that will make this easier? Drill a round hole and then use a square needle file? Link to post Share on other sites More sharing options...
Coombe Barton Posted October 29, 2011 Share Posted October 29, 2011 Drill a round hole and then use a square needle file? To do that for the size of hole required you'd need something the size of a watchmaker's escapement file. Not cheap. Link to post Share on other sites More sharing options...
clarkea1 Posted October 29, 2011 Share Posted October 29, 2011 Some form of broach? Broaches are commonly used in metal to cut square holes but I'm not sure if you could get something small enough? Essentially you'd start with a round hole (undersize) and then push a broach through it to turn it into a square hole. They have series of progressively larger teeth which gradually remove the corners of the circular hole to form a square one. See: http://www.dumont.com/prod3c.html For them to work in metal you tend to need a broaching press to force them through the metal but in plastic I expect you could use one "freehand" or in some kind of jury-rigged press setup. I'm not sure if they're available down to 2mm, or of price, but they're essentially how square holes would be produced in metal (except for processes like spark or wire erosion which are a bit more hardcore engineering!). Alternatively, and I haven't given this too much thought, but how about a square piece of brass attached to a soldering iron, and effectively melt the holes in? Iain Rice in one of his wagon books mentions melting in handrails etc without too much trouble but you'd probably be advised to experiment with some scrap plastic first to see if the method works. Regards Alastair Link to post Share on other sites More sharing options...
RMweb Gold The Fatadder Posted October 29, 2011 Author RMweb Gold Share Posted October 29, 2011 I was going to do this but chickened out! (I do have four sets to do!) My thoughts involved either one 'large' hole and file square or four tiny holes and knife work. Neither really appealed and seeing the strong chance of making a co pig's ear of it I convinced myself they dont really show. I too would welcome an easy solution. (I thought about new etched sides, which would also solve the other problems of the extra window* and the weird glazing, but fails on the inconvenience and cost.) * I recently tried filling in one of these as an experiment, but have still not got it smooth enough. I've done one of the windows so far and I think that I have got it smooth enough. it certainly feels like it. Etched sides would have been a good option, though dealing with the inset door in the guards compartment would have been tricky I guess. At the moment my thinking was between the 4 hole method (although it will be tight getting 4 holes in the space required) or one hole and open out. I have had a good search without success at finding a 2mm square broache, I think the jewlers square file might be the way to go if I can find one with approximately a 2mm square. Once the square is cut out the plan is to cut a batch of 2mm square sections of plasticard, pre drilled with the hole for the handle then mount them into the coach side. Link to post Share on other sites More sharing options...
Kenton Posted October 29, 2011 Share Posted October 29, 2011 Am I the only one who doesn't understand why you need a square hole in the first place and thinks that there is as fundamental design flaw in having the square pegs in the first place? Link to post Share on other sites More sharing options...
chrisf Posted October 29, 2011 Share Posted October 29, 2011 Kenton has raised a point that I will put another way. The hole is not square for it has rounded corners. I would get the Comet side for the C60/62 corridor third, clamp it somehow to the brake composite and use the apertures for the door and grab handles as templates. Chris Link to post Share on other sites More sharing options...
Hightower Posted October 29, 2011 Share Posted October 29, 2011 Surely you need something like this? Link to post Share on other sites More sharing options...
Guest stuartp Posted October 29, 2011 Share Posted October 29, 2011 I assume the hole doesn't need to go all the way through ? Try drilling a 2mm hole to the depth required, then chop out the corners with the very tip of a round-ended X-acto blade used as a chisel/scraper. I've used this in the past to make cab door handle recesses on Class 26s. Mind you, I didn't have 32 to do. Link to post Share on other sites More sharing options...
kandc_au Posted October 30, 2011 Share Posted October 30, 2011 Hightower, You beat me to it. Khris Link to post Share on other sites More sharing options...
Guest Natalie Graham Posted October 30, 2011 Share Posted October 30, 2011 To do that for the size of hole required you'd need something the size of a watchmaker's escapement file. Not cheap. No you don't. An ordinary needle file tapers to a point, I just measured one that was lying on the bench and there's a good 25mm before it gets to 2mm square. You don't have to have the whole file through the hole just work with the tip. Link to post Share on other sites More sharing options...
Coombe Barton Posted October 30, 2011 Share Posted October 30, 2011 No you don't. An ordinary needle file tapers to a point, I just measured one that was lying on the bench and there's a good 25mm before it gets to 2mm square. You don't have to have the whole file through the hole just work with the tip. Ah - but to get a square corner you really need to use a triangular file so that you can get rid of the radius in the corner. However we're trying to solve a problem of a large number of holes that have to be the same. That's the difficulty. Nono of us have come up with that yet. Link to post Share on other sites More sharing options...
RMweb Gold Happy Hippo Posted October 30, 2011 RMweb Gold Share Posted October 30, 2011 I have a press tool that is used to punch holes that are round/square rectangular into metal sheet. Obviously it's meant for stuff a lot bigger and hardier than plastic sheet, but the principle remains the same. Punch out the square hole and back it with a sheet of plastikard with the hole pre-drilled for the handle. Making the punch would not be a problem; making the female part could pose some problems. I'd be more worried about accurately placing the carriage side in the press and getting the hole in the correct place. The other, lazy, way of doing this is ask how many people would be able to say that's the wrong shape for normal viewing distances. I know I couldn't. Regards Richard Link to post Share on other sites More sharing options...
Il Grifone Posted October 30, 2011 Share Posted October 30, 2011 Ah - but to get a square corner you really need to use a triangular file so that you can get rid of the radius in the corner. However we're trying to solve a problem of a large number of holes that have to be the same. That's the difficulty. Nono of us have come up with that yet. There's no need to get rid of all the radius as the holes are round cornered. The necessity of getting all the holes the same is why I convinced myself to leave well alone. I think some sort of jig would be almost essential. I'm not keen on melting things in. One slip could be disastrous. (Guess how I know?) Link to post Share on other sites More sharing options...
billbedford Posted October 31, 2011 Share Posted October 31, 2011 I think you will need to make something like this:- This is simply a piece of 2mm steel with a hole and two 'V' grooves in the end. it can be cleaned up a bit with a small grinding point in a dremel or similar. You can use it either mounted in a graver handle or as a punch/chisel with a hammer. Link to post Share on other sites More sharing options...
chrisf Posted October 31, 2011 Share Posted October 31, 2011 Ah - but to get a square corner you really need to use a triangular file so that you can get rid of the radius in the corner. However we're trying to solve a problem of a large number of holes that have to be the same. That's the difficulty. Nono of us have come up with that yet. Refer to post 8 above! Chris Link to post Share on other sites More sharing options...
billbedford Posted November 1, 2011 Share Posted November 1, 2011 To do that for the size of hole required you'd need something the size of a watchmaker's escapement file. Not cheap. You use a triangular file to make a square hole because unless you hold the file exactly square to the hole on each stroke you will get an oversquare, or cushion shaped, hole. A triangular file allows you to work on each face of the hole with the minimum effect on the other faces. Link to post Share on other sites More sharing options...
brightspark Posted November 1, 2011 Share Posted November 1, 2011 Not being pedantic but I just thought I would let you know that the correct term for a triangular file is a 'three square file'. My good deed for the day is done. Although this is no help in making a square hole. Link to post Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.